Airlift pump

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An airlift pump, powered by compressed air, raises fluid by entraining gas to reduce its density.
1. air supply
2. liquid supply
3. air inlet port
4. air supply line
5. air port
6. air outlet
7. fluid intake
8. riser tube
9. air liquid mixture
10. pump outlet
L: liquid, usually wastewater
LL: liquid level
V: Vessel
G: Gravel or solids. Airliftpump1.PNG
An airlift pump, powered by compressed air, raises fluid by entraining gas to reduce its density.
1. air supply
2. liquid supply
3. air inlet port
4. air supply line
5. air port
6. air outlet
7. fluid intake
8. riser tube
9. air liquid mixture
10. pump outlet
L: liquid, usually wastewater
LL: liquid level
V: Vessel
G: Gravel or solids.

An airlift pump is a pump that has low suction and moderate discharge of liquid and entrained solids. The pump injects compressed air at the bottom of the discharge pipe which is immersed in the liquid. The compressed air mixes with the liquid causing the air-water mixture to be less dense than the rest of the liquid around it and therefore is displaced upwards through the discharge pipe by the surrounding liquid of higher density. Solids may be entrained in the flow and if small enough to fit through the pipe, will be discharged with the rest of the flow at a shallower depth or above the surface. Airlift pumps are widely used in aquaculture to pump, circulate and aerate water in closed, recirculating systems and ponds. Other applications include dredging, underwater archaeology, salvage operations and collection of scientific specimens.

Contents

Principle

The only energy required is provided by compressed air. [1] This air is usually compressed by a compressor or a blower. The air is injected in the lower part of a pipe that transports a liquid. By buoyancy the air, which has a lower density than the liquid, rises quickly. By fluid pressure, the liquid is taken in the ascendant air flow and moves in the same direction as the air. The calculation of the volume flow of the liquid is possible thanks to the physics of two-phase flow.

Use

Inventor

The first airlift pump is considered to be invented by the German engineer Carl Emanuel Löscher  [ de ] in 1797.

Advantages and disadvantages

Advantages

Disadvantages

Movement of the liquide by injection of compressed air for micro-organism cultivation in the CiYOU, bioreactor from Biorea Technologie Airlift 01.png
Movement of the liquide by injection of compressed air for micro-organism cultivation in the CiYOU, bioreactor from Biorea

Design improvements

A geyser pump, an improved airlift pump, powered by compressed air, raises fluid by forcing rising bubbles to displace fluid.
50. air supply
52. air inlet port
58. liquid supply
60,62. air supply lines
64. upper end of air tank 86
66,82. air ports
70. upper air inlet of u-shaped elbow 74
76 air outlet
84. fluid intake
65. riser tube
88. displaced liquid
90. pump outlet
L: liquid, usually wastewater
LL: liquid level
VVV: vessel
G: gravel or solids Geyserpump.PNG
A geyser pump, an improved airlift pump, powered by compressed air, raises fluid by forcing rising bubbles to displace fluid.
50. air supply
52. air inlet port
58. liquid supply
60,62. air supply lines
64. upper end of air tank 86
66,82. air ports
70. upper air inlet of u-shaped elbow 74
76 air outlet
84. fluid intake
65. riser tube
88. displaced liquid
90. pump outlet
L: liquid, usually wastewater
LL: liquid level
VVV: vessel
G: gravel or solids

A recent (2007) variant called the "geyser pump" can pump with greater suction and less air. It also pumps proportionally to the air flow, permitting use in processes that require varying controlled flows. It arranges to store up the air, and release it in large bubbles that seal to the lift pipe, raising slugs of fluid. [6]

Airlift pump (left) compared to geyser pump (right) Airlift Pump vs Geyser Pump.JPG
Airlift pump (left) compared to geyser pump (right)

See also

Related Research Articles

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Cavitation in fluid mechanics and engineering normally refers to the phenomenon in which the static pressure of a liquid reduces to below the liquid's vapour pressure, leading to the formation of small vapor-filled cavities in the liquid. When subjected to higher pressure, these cavities, called "bubbles" or "voids", collapse and can generate shock waves that may damage machinery. These shock waves are strong when they are very close to the imploded bubble, but rapidly weaken as they propagate away from the implosion. Cavitation is a significant cause of wear in some engineering contexts. Collapsing voids that implode near to a metal surface cause cyclic stress through repeated implosion. This results in surface fatigue of the metal, causing a type of wear also called "cavitation". The most common examples of this kind of wear are to pump impellers, and bends where a sudden change in the direction of liquid occurs. Cavitation is usually divided into two classes of behavior: inertial cavitation and non-inertial cavitation.

<span class="mw-page-title-main">Pump</span> Device that imparts energy to the fluids by mechanical action

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Airlift is the act of transporting people or cargo from point to point using aircraft.

<span class="mw-page-title-main">Venturi effect</span> Reduced pressure caused by a flow restriction in a tube or pipe

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A vacuum ejector, or simply ejector is a type of vacuum pump, which produces vacuum by means of the Venturi effect.

<span class="mw-page-title-main">Dredging</span> Excavation of sediment, usually under water

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<span class="mw-page-title-main">Injector</span> Type of pump using high pressure fluid to entrain a lower pressure fluid

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<span class="mw-page-title-main">Airlift (dredging device)</span> Dredging device using injected air to move water and entrained load up a pipe

An airlift is device based on a pipe, used in nautical archaeology to suck small objects, sand and mud from the sea bed and to transport the resulting debris upwards and away from its source. It is a type of suction dredge. A water dredge or water eductor may be used for the same purpose.

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<span class="mw-page-title-main">Water eductor</span> Type of pump used in archeology

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A hydraulic compressor is a means of compressing air useing hydraulic energy. There ate two very different types of machine referred to as hydraulic compessors.

High-density solids pumps are hydrostatically operating machines which displace the medium being pumped and thus create a flow.

The Glossary of Geothermal Heating and Cooling provides definitions of many terms used within the Geothermal heat pump industry. The terms in this glossary may be used by industry professionals, for education materials, and by the general public.

References

  1. "Water lifting devices". Food and Agriculture Organization (FAO) of the United Nations. Retrieved 17 April 2021.
  2. 1 2 Cahoon, LB; Lindquist, DG; Clavijo, IE; Tronzo, CR (1992). "Sampling small invertebrates at the sediment-water interface". In: Cahoon, LB. (Ed.) Proceedings of the American Academy of Underwater Sciences Twelfth Annual Scientific Diving Symposium "Diving for Science 1992". Held September 24–27, 1992 at the University of North Carolina at Wilmington, Wilmington, NC. American Academy of Underwater Sciences. Archived from the original on July 5, 2013. Retrieved 2013-04-05.{{cite journal}}: CS1 maint: unfit URL (link)
  3. "Air quantity calculation" (PDF). Archived from the original (PDF) on 2006-10-22. (1.86 MB)
  4. Airlift basic calculation Archived 2011-07-07 at the Wayback Machine
  5. New Pump Technology May Improve Small Flows, WVU NCSFC Clearinghouse Archived 2010-12-02 at the Wayback Machine Accessed 2011-3-21
  6. Patent Application number: 11/654,448 , January 17, 2007, Inventor: Masao Kondo

Sources